/* $Id: points.c,v 1.6 1997/03/08 02:04:27 brianp Exp $ */

/*
 * Mesa 3-D graphics library
 * Version:  2.2
 * Copyright (C) 1995-1997  Brian Paul
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the Free
 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */


/*
 * $Log: points.c,v $
 * Revision 1.6  1997/03/08 02:04:27  brianp
 * better implementation of feedback function
 *
 * Revision 1.5  1997/02/09 18:43:52  brianp
 * added GL_EXT_texture3D support
 *
 * Revision 1.4  1997/01/09 19:48:00  brianp
 * now call gl_texturing_enabled()
 *
 * Revision 1.3  1996/11/08 02:21:21  brianp
 * added null drawing function for GL_NO_RASTER
 *
 * Revision 1.2  1996/09/15 14:18:37  brianp
 * now use GLframebuffer and GLvisual
 *
 * Revision 1.1  1996/09/13 01:38:16  brianp
 * Initial revision
 *
 */


#include "context.h"
#include "feedback.h"
#include "dlist.h"
#include "macros.h"
#include "pb.h"
#include "span.h"
#include "texture.h"
#include "types.h"
#include "vb.h"

/**********************************************************************/
/*****                    Rasterization                           *****/
/**********************************************************************/


/*
 * There are 3 pairs (RGBA, CI) of point rendering functions:
 *   1. simple:  size=1 and no special rasterization functions (fastest)
 *   2. size1:  size=1 and any rasterization functions
 *   3. general:  any size and rasterization functions (slowest)
 *
 * All point rendering functions take the same two arguments: first and
 * last which specify that the points specified by VB[first] through
 * VB[last] are to be rendered.
 */



/*
 * Put points in feedback buffer.
 */
static void feedback_points( GLcontext *ctx, GLuint first, GLuint last )
{
   struct vertex_buffer *VB = ctx->VB;
   GLuint i;
   GLfloat invRedScale   = ctx->Visual->InvRedScale;
   GLfloat invGreenScale = ctx->Visual->InvGreenScale;
   GLfloat invBlueScale  = ctx->Visual->InvBlueScale;
   GLfloat invAlphaScale = ctx->Visual->InvAlphaScale;

   for (i=first;i<=last;i++) {
      if (VB->Unclipped[i]) {
         GLfloat x, y, z, w, invq;
         GLfloat color[4], texcoord[4];

         x = VB->Win[i][0];
         y = VB->Win[i][1];
         z = VB->Win[i][2] / DEPTH_SCALE;
         w = VB->Clip[i][3];

         /* convert color from integer back to a float in [0,1] */
         if (ctx->Light.ShadeModel==GL_SMOOTH) {
            /* smooth shading - colors are in fixed point */
            color[0] = FixedToFloat(VB->Color[i][0]) * invRedScale;
            color[1] = FixedToFloat(VB->Color[i][1]) * invGreenScale;
            color[2] = FixedToFloat(VB->Color[i][2]) * invBlueScale;
            color[3] = FixedToFloat(VB->Color[i][3]) * invAlphaScale;
         }
         else {
            /* flat shading - colors are integers */
            color[0] = VB->Color[i][0] * invRedScale;
            color[1] = VB->Color[i][1] * invGreenScale;
            color[2] = VB->Color[i][2] * invBlueScale;
            color[3] = VB->Color[i][3] * invAlphaScale;
         }
         invq = 1.0F / VB->TexCoord[i][3];
         texcoord[0] = VB->TexCoord[i][0] * invq;
         texcoord[1] = VB->TexCoord[i][1] * invq;
         texcoord[2] = VB->TexCoord[i][2] * invq;
         texcoord[3] = VB->TexCoord[i][3];

         FEEDBACK_TOKEN( ctx, (GLfloat) GL_POINT_TOKEN );
         gl_feedback_vertex( ctx, x, y, z, w, color,
                             (GLfloat) VB->Index[i], texcoord );
      }
   }
}